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The condensation product of 7-acetyl-6-azaindole and Girard's T reagent ((E)-2-(2-(1-(1H-pyrrolo[2,3-c]pyridin-7-yl)ethylidene)hydrazineyl)-N,N,N-trimethyl-2-oxoethan-1-aminium, HL ligand) was used as a ligand in the reaction with Cu(BF4)2·6H2O and NaN3. The reaction led to the formation of a binuclear Cu(II) complex containing two end-to-end (di-µ-1,3-N3) azide bridges, as well as two NNO-donor hydrazone ligands, forming an axially elongated square pyramidal geometry around each Cu(II) center. This end-to-end (di-µ-1,3-N3) azide bridge binding mode has not yet been reported, in Cu(II) complexes containing the NNO-donor hydrazone ligands, which makes the structure of the complex even more interesting for further studies. The complex was characterized by elemental analysis, IR spectroscopy and X-ray crystallography, and it was found that it crystallizes in the triclinic space group P-1 with the asymmetric unit comprising one Cu(II) centre, zwitterionic ligand L, one azide (N3 -) ligand and BF4 - counter anion. Examination of antimicrobial activity of the complex shows higher antifungal and antibacterial activity towards tested Gram-positive bacteria in comparison to the hydrazone ligand, with the antifungal activity of the complex even being comparable to the activity of amphotericin B. [ABSTRACT FROM AUTHOR]

Two new Zn(II) complexes with tridentate hydrazone-based ligands (condensation products of 2-acetylthiazole) were synthesized and characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy and single crystal X-ray diffraction methods. The complexes 1, 2 and recently synthesized [ZnL3(NCS)2] (L3 = (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)ethan-1-aminium) complex 3 were tested as potential catalysts for the ketone-amine-alkyne (KA2) coupling reaction. The gas-phase geometry optimization of newly synthesized and characterized Zn(II) complexes has been computed at the density functional theory (DFT)/B3LYP/6–31G level of theory, while the highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO and LUMO) energies were calculated within the time-dependent density functional theory (TD-DFT) at B3LYP/6-31G and B3LYP/6-311G(d,p) levels of theory. From the energies of frontier molecular orbitals (HOMO–LUMO), the reactivity descriptors, such as chemical potential (μ), hardness (η), softness (S), electronegativity (χ) and electrophilicity index (ω) have been calculated. The energetic behavior of the investigated compounds (1 and 2) has been examined in gas phase and solvent media using the polarizable continuum model. For comparison reasons, the same calculations have been performed for recently synthesized [ZnL3(NCS)2] complex 3. DFT results show that compound 1 has the smaller frontier orbital gap so, it is more polarizable and is associated with a higher chemical reactivity, low kinetic stability and is termed as soft molecule.

Testosterone is one of the androgens synthesized from cholesterol as a precursor in the Leydig cells of testes. Since the ionization efficiency of testosterone in matrix-assisted laser desorption ionization (MALDI) is quite low, visualization of testosterone by using MALDI-imaging mass spectrometry (MALDI-IMS) has been considered difficult. To overcome this problem, we used two types of on-tissue derivatization techniques, which were achieved by pyridine sulfur trioxide and Girard's T (GT) reagent, to introduce a polar group into testosterone molecule with the aim to increase the sensitivity. Derivatization by use of GT reagent provided excellent results, superior to those obtained with pyridine sulfur trioxide, in terms of ionization efficiency, molecular specificity, and tissue damage. In GT derivatized testis tissues of mice treated with human chorionic gonadotropin (hCG), testosterone was broadly observed both inside and outside the seminiferous tubules by using an iMScope. To evaluate our imaging results, we performed quantification experiments of underivatized testosterone extracted from hCG-treated testes and control testes using LC-MS/MS. We confirmed the 256-fold concentration change between hCG-treated tissues and control tissues. We also confirmed the 228-fold change in detected peak intensities between hCG-treated tissue sections and control tissue sections in imaging results. We consider our tissue preparation methods for IMS provide high sensitivity with high precision. In addition, high-spatial definition IMS was also available, and we confirmed testosterone had mainly accumulated on the surface of the Leydig cells. [ABSTRACT FROM AUTHOR]

Square-planar azido Ni(II) complex with condensation product of 2-(diphenylphosphino)benzaldehyde and Girard's T reagent was synthesized and its crystal structure was determined. Cytotoxic activity of the azido complex and previously synthesized isothiocyanato, cyanato and chlorido Ni(II) complexes with this ligand was examined on six tumor cell lines (HeLa, A549, K562, MDA-MB-453, MDA-MB-361 and LS-174) and two normal cell line (MRC-5 and BEAS-2B). All the investigated nickel(II) complexes were cytotoxic against all tumor cell lines. The newly synthesized azido complex showed selectivity to HeLa and A549 tumor cell lines compared to the normal cells (for A549 IC was similar to that of cisplatin). Azido complex interferes with cell cycle phase distribution of A549 and HeLa cells and possesses nuclease activity towards supercoiled DNA. The observed selectivity of the azido complex for some tumor cell lines can be connected with its strong DNA damaging activity. [ABSTRACT FROM AUTHOR]

Square-planar isocyanate and chloride Ni(II) complexes with tridentate PNO condensation product of 2-(diphenylphosphino)benzaldehyde and Girard’s T reagent have been synthesized and their crystal structures were determined. These Ni(II) complexes with different monodentate ligands, chloride, cyanate, and thiocyanate were tested for their antimicrobial activities against pathogenic microorganisms. The ligand and Ni(II) complexes were active not only against laboratory control strains of bacteria and yeast, but also on clinical isolates ofEscherichia coliandPseudomonas aeruginosastrains resistant to most of the clinically used antibiotics. [ABSTRACT FROM AUTHOR]

Abstract: Quantitative analysis of oligosaccharide mixtures and their derivatives by electrospray ionization mass spectrometry (ESI MS) is challenging, for example, due to different affinities of the analytes to alkali ions. To overcome this source of discrimination and to enhance signal intensity, labeling studies with cellobiose as model compound were performed with the goal to develop a rapid, easy, and robust method. Hydrazone formation with the permanently charged Girard’s T reagent as well as reductive amination with five different charge providing amines were studied under various conditions. In both reaction types, the removal of water turned out to be the critical step because only under these conditions are the reactions pushed to completion. By working with only a slight excess of reagents, no purification is necessary to achieve excellent signal/noise ratios, avoiding further sources of discrimination. Comparing various reducing agents with respect to their selectivity and stability in the acidic reaction medium, 2-picoline borane turned out to be superior to the commonly used sodium cyanoborohydride. Thus, by replacement of the toxic NaCNBH3 by the more selective and stable, non-toxic 2-picoline borane, complete reductive amination with low amounts of reagents and without unlabeled alditol formation was achieved with o-aminobenzoic acid, a useful reagent for ESI MS in negative mode. For MS in positive mode Girard’s T derivatization was very suitable. [ABSTRACT FROM AUTHOR]

Abstract: The condensation of 2-formyl-pyridine with Girard’s T reagent yields a new hydrazone in the form of an ammonium quaternary salt: [H(2-PyGT)]Cl. This tridentate ligand is readily soluble in water and reacts with iron(III) or copper(II) chlorides to give [Fe(2-PyGT)Cl3] (1) or [Cu(2-PyGT)Cl2]·(H2O) (2) complexes, respectively. Single-crystal X-ray studies in 1 and 2 reveal that the coordination reaction gives rise to the deprotonation of the organic ligand that is coordinated using its NNO donor atoms in the form of a zwitterion species. The coordination spheres around the transition metal ions in complexes 1 and 2 are quite different. In 1, the iron site adopts a distorted octahedral coordination sphere, while the Cu(II) ions in 2 show a distorted tetragonal-pyramid geometry. As expected, the magnetic properties of these compounds reveal only weak antiferromagnetic interaction between spin carriers. [ABSTRACT FROM AUTHOR]

Abstract: Carbonyl and sulphur compounds were investigated in freshly distilled Calvados and Cognac. Forty-eight aldehydes and ketones were identified in both products using specific extraction, with Girard''s T reagent supported on silica-gel. The recovery procedure of these compounds in a high ethanolic medium was optimized. Samples contained a majority of saturated aliphatic aldehydes and ketones. The presence of unsaturated aliphatic aldehydes and ketones, such as alkenals, oct-1-en-3-one, 6-methylhept-5-en-2-one and -damascenone, was also detected. Numerous terpenoic or norisoprenoic carbonyl compounds were characterized and seem to be specific to Cognac. Twenty-seven sulphur compounds were quantified in the same samples; small amounts of thiols were detected. Concentrations of dimethyl disulphide were from 50–500μgL−1 of pure alcohol (PA), and a high content of dibutyl sulphide (20–100μgL−1 of PA) was recorded. Concentrations of ethyl propyl sulphide and diethyl sulphide, which were not significant in Calvados, were above 25μgL−1 of PA in Cognac. 2- and 3-thiophenecarboxaldehyde were also quantified, and concentrations as high as 1000μgL−1 in some samples, were the most important in Cognac. The ratio of 3- and 2-thiophenecarboxaldehyde was higher than 10 for Calvados, but was less than 0.5 for Cognac. Although weak concentrations of methional were recorded, this may contribute to the overall aroma of these two spirits due to extremely low detection threshold. The total concentration of sulphur compounds in Cognac samples was five to six times that of Calvados samples. [Copyright &y& Elsevier]